Aerosols for therapeutic purposes are generated and delivered to a desired location within a user's or patient's body with aerosol delivery devices. A fluid or liquid (i.e., medicament) to be aerosolised or nebulised is supplied to an aerosol generator of the aerosol delivery device, the fluid or liquid is aerosolised or nebulised by the aerosol generator and the resultant aerosol is supplied to the user or patient.
The fluid or liquid may be aerosolised or nebulised in the aerosol generator by a vibratable head. The properties of the vibratable head of the aerosol generator are of paramount importance for the quality of the generated aerosol and the accuracy of the aerosol dosage. At the same time, the vibratable head is also generally very sensitive. Deviations in the structure or the arrangement of the vibratable head may adversely affect the oscillatory or vibrating motion of the head during aerosol generation and thus compromise the quality of the generated aerosol and the aerosol dosage accuracy.
An aerosol generator of this vibratable head type is disclosed in DE 10 2005 006 375 A1. In particular, DE 10 2005 006 375 A1 discloses an aerosol generator for inhalation therapy devices in which an oscillatable assembly, consisting of at least a membrane and an oscillation generator, is mounted in an encapsulating means.
Vibratable heads are known which comprise a support member and a membrane supported by the support member. One or more elements of the vibratable head may be secured to the support member, e.g., by an adhesive joint. In order to improve the durability of such an adhesive joint, a portion of the support member to which the adhesive is to be applied may be roughened. To date, this surface roughening has been achieved by sandblasting.
However, roughening a portion of the support member of the vibratable head by sandblasting presents numerous problems. For one thing, this process is laborious and time-consuming, further requiring the additional steps of cleaning and drying the support member before the application of an adhesive. For another thing, the sandblasting step has to be performed manually, resulting in undesired deviations or variations in the obtained surface structures, and cannot be integrated into a production line. Moreover, even if sandblasting masks are used, a well-defined and sharp delimitation of the roughened surface area is difficult if not impossible to achieve. Further, such masks are prone to abrasive wear and thus have to be replaced on a regular basis.
Hence, there remains a need for a method of manufacturing a vibratable head which allows for the vibratable head to be fabricated in an efficient and precise manner.
The process of imparting desired structures to surfaces by laser structuring has, thus far, mainly been used in the automotive industry and for providing printing patterns on print rollers. An overview of this process is given in the dissertation “Oberflächenstrukturieren mit ultrakurzen Laserpulsen” by M. Weikert, University of Stuttgart, Herbert Utz Verlag GmbH, 2006, Germany.